Subsea Gate Valve Bore Coating for Erosion Resistance
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Solution Overview
Problem
Gate valves in the oil and gas industry, particularly subsea valves, experience premature failure due to erosion and cavitation caused by particles in the fluid, despite existing coatings only being applied to sliding surfaces, leading to reduced service life and potential costly equipment retrieval.
Innovation Solution
Applying a hard coating, such as tungsten carbide or diamond-like carbon, to the internal bore surface of the gate and seat surfaces exposed to fluid flow, which are not typically coated in standard designs, to prevent erosion and cavitation, using techniques like HVOF, HVAF, or CVD for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If coating is applied only to sliding surfaces (gate and seats), then manufacturing cost and complexity are minimized, but service life is reduced due to erosion and cavitation damage on internal bore surfaces
Solution Approach 1:
The patent applies coating selectively to specific surfaces that require protection (sealing surfaces and internal bore surfaces) while leaving other surfaces uncoated. This local quality approach ensures that coating is applied only where erosion and cavitation resistance is needed, rather than uniformly across the entire valve, thus extending service life without unnecessarily increasing complexity
Solution Approach 2:
The patent uses hard-facing materials (such as tungsten carbide or ceramic coatings) applied to the valve's internal surfaces. These composite material structures combine the base metal with a harder, more erosion-resistant coating layer, creating a composite structure that resists cavitation and erosion while maintaining the structural integrity of the original valve
2Reliability
If hard-facing technique is applied to internal bore surfaces, then resistance to erosion and cavitation is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies hard-facing coating only to the internal bore surfaces and sealing surfaces that are directly exposed to fluid flow and susceptible to erosion and cavitation, rather than coating the entire valve. This localized approach improves reliability where needed while minimizing the additional manufacturing cost associated with hard-facing processes
Solution Approach 2:
The patent applies coating to the critical surfaces that require protection against erosion and cavitation, using a partial action approach rather than coating the entire valve. This ensures adequate protection on the internal bore surfaces where fluid flow causes damage, while avoiding unnecessary coating on other surfaces, thus balancing reliability improvement with manufacturing cost
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coating significantly extends the service life of the valve by reducing erosion and cavitation damage, even under turbulent flow conditions and frequent operation, thereby minimizing the risk of costly subsea equipment failures.
Implementation Method 1
A fluid with particles can cause erosion of the gate and seats of the valves during operation
Implementation Method 2
the rapid changes in pressure can cause cavitation on the valve parts, resulting in leakage, further damage and eventually total failure of the valve
Data Source
AI summary
The invention provides a gate valve for control of production of petroleum, distinctive in that the valve comprises a coating or hard facing on the internal bore surface exposed to flow of petroleum and associated fluids and solids.